Manual for Cytology - IARC Screening Group

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20 Manual for Cytology Preparation and fixation for pap staining Immediately after withdrawing, detach the needle, draw air into the syringe, reattach the needle and express the material in the needle onto a slide. Needle tip is brought into light contact with the slide and the aspirate is carefully expressed without spraying into the air, which can cause air-drying and also can form aerosols, which are potentially infectious. Preparing proper smears is critical for the end results. No matter how expertly the aspiration is performed, if the slides are not interpretable, the procedure is totally worthless for cytologic diagnosis. (Smearing technique is better demonstrated than described). An ideal aspirate is of creamy consistency with numerous cells suspended in a small amount of tissue fluid without admixture with blood. Such aspirates are smeared immediately using another slide or cover slip or with the needle itself and dropped into the fixative. At the beginning of the smearing process, while the material is still in a drop on the slide, the surface area for evaporation is relatively small and hence a short delay will not cause significant air-drying. Once the smear has been made, the surface areas are greatly increased and the thickness of the smear is greatly diminished. Thus from the instant the smear is made, air-drying proceeds extremely rapidly; hence the urgency for fixation. Material diluted with blood can be spread like a peripheral smear, where particles tend to come to the edge of the smear. Larger particles can be crushed gently by firm flat pressure. Undue pressure can result in crush / smearing artifact. If can also be spread in a circular motion with the needle itself, when particles and cells tend to distribute around the periphery of the smear. In either case, smear should not go to the edges of the slides, where particles can be lost over the edges. Outline of a perfect smear is completely contained on the slide without going to any of the edges. The cells must be delicately and thinly smeared with minimal distortion and fixed according to the stain to be used. However, spreading the cells too thinly as well as preparing too many smears is an error because of cellular distortion or dilution. Thus the smears must be of adequate thickness. Obtaining optimal smear is a fine balance between too thick and too thin smears (or fixation and crush artifacts) and comes with experience. If a large amount of material is aspirated, multiple smears can be made, both air-dried and wet fixed which are complementary to each other. Extra smears can be used for special stains or other supplementary techniques. (While taking multiple smears, do not prepare all the smears and then go back and fix them. Fix the smears as soon as they are made to avoid drying). Smears can also be prepared indirectly by centrifugation, filtration etc. In lymph node aspiration, a cell suspension can be prepared in addition to direct smears. Other systems like “cell print” are now available for cell collection and preparation. In some centres, needles
Collection and Preparation of Material for Cytodiagnosis and syringe rinse preparations are routinely done and smears prepared by centrifugation or filtration. These types of indirect smears provide thin film of concentrated cells in a clear background from samples of low / high cellularity. This is ideal for special stains and immunocytochemistry. Note: In guided FNA, once the needle is in the mass, the procedure and smear preparation is similar to plain FNA, including the cutting motion with the needle as well as preparation and fixation of smears. Causes of unsatisfactory smears Unsatisfactory smears can be due to non-representative / inadequate samples or due to poor quality of preparation (thick smears, extreme admixture with blood, delayed fixation, over staining etc). Attention to matters of technique regarding the procedure and preparation of smears will considerably reduce the number of unsatisfactory smears received in a cytology lab. Clinical correlation and final interpretation by the pathologist Final diagnosis on FNA is based on clinical assessment prior to the aspiration procedure, observations during the procedure as well as microscopic evaluation. Optimal diagnosis is obtained when the same pathologist correlates the clinical features, performs the aspiration and evaluates the smears. When this is not possible, close communication between clinician and pathologist helps to maintain high quality of diagnosis and safeguards against errors. Inaccurate, misleading, incomplete or absent clinical information can be important sources of error. Clinical information is critical and is a part of FNA diagnosis as the morphological features may vary with the site of FNA and have to be correlated with the site of aspiration and other investigations for a meaningful diagnosis. Thus, systematic inclusion of clinical and lab data should be considered as part of the procedure. The technique (aspirator), morphological interpretation (pathologist) and clinical information (clinician) constitute a diagnostic triad on which the FNA diagnosis rests. It is preferable not to report on technically poor slides or give a definite diagnosis without adequate clinical information and correlation. Clinical data serves as a safeguard in avoiding errors. Other Quality control Measures In addition to details of technique (procedure, preparation, quality of materials used) and clinical correlation; other routine quality control practices regarding specimen reception (checking patient details, identification of slides, number of slides from each patient, labeling the slides), preparation and maintenance of stains, staining procedure, mounting, record keeping etc. are applicable to FNA also for optimal quality of diagnosis. 21
Page 1: Manuals for Training in Cancer Cont
Page 5: Dr. S. P. AGARWAL M. S. (Surg.) M.
Page 9 and 10: 1 Role of Diagnostic Cytology Diagn
Page 11 and 12: Collection and Preparation of Mater
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Page 25 and 26: Cytopreparatory Techniques of Serou
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Page 29 and 30: C. Special Purpose Fixative Fixatio
Page 31 and 32: Staining Methods in Cytology e.Clea
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Page 37 and 38: Appendix: Organisation of Cytopatho
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Page 41 and 42: Appendix: Minimum Requirements for
Page 43 and 44: ACKNOWLEDGEMENTS Compiled and edite

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